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<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
         
        //ES5 方式
        function join(){
            var str = "";
            for (var i = 0;i < arguments.length; i++){
                if(i == 0){
                    str = arguments[i];
                }else{
                    str += "|" + arguments[i];
                }
            }
            return str;
        }
        console.log(join("hello","world"));
        //ES6 方式
        function join2(...strs){
            var str = "";
            for (var i = 0; i <strs.length; i++){
                if(i==0){
                    str = strs[i];
                }else{
                    str +="|" + strs[i];
                }
            }
            return str;
        }
    </script>
</body>
</html>